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German astronomers fight for dark sky preserve

Light pollution from bustling cities infuriates astronomers. And in heavily industrialized Germany, a good dark corner can be hard to find. Astronomers have found the darkest one - if only they can protect it.

The darkest night sky in Germany can be found near a town called Gülpe, some 120 kilometers west of Berlin. Just 160 people live in the tiny town in the German state of Brandenburg. Combine that with a nearby local nature reserve and the Havel river, and their night sky shines with the most stars of anywhere in Germany.

That setting was perfect for a gathering of astronomers earlier this month. Among them was Andreas Hänel, an astronomer from the western German city of Osnabrück. Hänel has been appointed to protect the pitch-black region from wayward sources of light. He has also formally requested that Gülpe be declared a "Dark Sky Park," or a natural reserve aimed at protecting the night sky.

The darkest skies in Germany can be seen along the Havel river near the town of Gülpe

Light pollution

In many heavily populated areas, stars are few and far between. Streetlamps, flashing billboards and even headlights from cars permeate the darkness, even from great distances.

The result is light pollution. Additionally, dust and molecules high up in the atmosphere scatter the light, ensuring the sky will never truly become dark. Throughout the night, cities are shrouded in a bell-shaped veil of ambient light, remaining far brighter than suburban regions around them.

That problem is well known to researchers, who have been conducting tests to see what kind of effect light pollution has on human beings and animals. That light disrupts the circadian rhythm of animals is no longer contended: Germany's Federal Agency for Nature Conservation has found that migratory birds lose their orientation, and foxes and bats lose the ability to tell whether it's night-time and therefore time to hunt.

But human hormones can also be thrown out of equilibrium. The permanent illumination of the night sky is comparable to leaving a television or a bedside lamp on overnight, according to biologists at the Leibniz Research Center for Working Environment and Human Factors (IfADo).

Streetlamps, particularly those with sodium bulbs and no shields, are the enemy of stargazers worldwide

The loss of night

But at the meeting in Gülpe, astronomers were of course more concerned with the way light pollution whitewashes the brilliance of the stars. In many places, the sky is just too bright to stargaze.

"Deep-sky objects such as gas clouds and galaxies can barely be seen in metropolitan areas," amateur astronomer Thomas Gursch told DW.

That's why professional stargazers are asking for the Gülpe region to be labeled a "star park." That status would help the area avoid excessive and disruptive sources of light from being installed nearby, guaranteeing clear night skies for astronomers - so long as the weather accommodates.

Darkest place in the world

The stargazing enthusiasts aim to file an application for recognition as an international star park to the US-based International Dark-Sky Association (IDA). The IDA is devoted to fighting light pollution. Were Gülpe to receive official designation by the IDA, it would become the first German star park to be so recognized.

Worldwide, there are twelve recognized star parks, with nine in the US alone. Beyond that, a region in Scotland and two in Hungary belong on the list of places where professional and amateur astronomers alike can enjoy their star-rich nights.